<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
     * { font-size: 30px;}   
    </style>
</head>
<body onclick="show()">
    <p> 这是P </p>
    <span> 这是span</span>
    <h1> 这是h1 </h1>
    <div> 这是div </div>
</body>
<script>
function show(){
    var obj =  event.srcElement;  //事件源对象
    alert( obj.tagName );
}

var a = 'abc';
var b = new String(a)

a.color = '蓝色'
b.color = '红色'

console.log( a == b);
console.log( a.color , b.color );

</script>
</html>